The present invention relates to a process for the detection of superimposed sheets, to the apparatus making it possible to perform the process and the application, in exemplified manner, to the examination of bundles of bank notes.
At present, apparatuses for detecting the superimposition of sheets are known, particularly in the banking field for detecting double bank notes. These apparatuses are based on the principle of mechanical detection by a roller, which senses the thickness of the notes travelling in the longitudinal direction on a drive roller. This type of apparatus causes problems of concentricity of the sensing roller and the drive roller and in addition only permits limited movement speeds, even in the case where the notes are fed in the direction of their greatest length.
Thus, the first objective of the present invention is to obviate the disadvantages of the prior art and to propose a process for the detection of superimposed sheets making it possible to partly or totally eliminate superimposed sheets from the sheets transported in the direction of their width.